Sarah Burke

Exciton Quenching at Grain Boundaries in C60 Thin Films Exciton lifetimes play a critical role in the performance of organic optoelectronic devices. In this work, we investigate how the presence of multiple rotational domains and therefore grain boundaries...

Read more about this cautionary tale and explanation of the effect on dynamics here, and make sure you know your films REALLY well…

pubs.acs.org/doi/abs/10.1...

Digging into why some films weren’t behaving the same in TR-ARPES, Rysa looked closer at the LEED data and noticed that there were tiny proportions of other film orientations. Looking with STM, we saw gap widening due to changes in the local dielectric, leading to exciton traps!

Continuing on the topic of defects, we recently found that even TINY amounts of disorder, leading to grain boundaries, in C60 films dramatically changes the lifetimes of excitons! Films that may seem good by LEED and ARPES may not be so great as reported by PhD student Rysa Greenwood in JPCL….

Intrinsic defect intolerance in the ultra-pure metal PtSn4 - Communications Materials Ultra-pure materials are essential for exploring intrinsic physics, yet achieving such purity often demands extensive crystal growth optimization. Here, the authors reveal that PtSn4 naturally exhibit...

And it turns out PtSn4 is kind of a Goldilocks material! Neighbouring compounds and even isoelectronic and nearly identically sized Pd have lower RRR!

Read about it here in Communications Materials (and admire JG Mair’s stunning painting as this issue’s cover art): www.nature.com/articles/s43...

The answer? Well, there really are just very, very few defects! Even when trying to grow “bad” crystals. So few defects we had to think about how to characterize uncertainties when counting from different size images and areas.

Photo of a painting of single crystal PtSn4 with reflections off crystal facets. Painting by Vancouver artist Jeff Mair.

Awhile ago, my colleague Alannah Hallas came knocking on my door about a new material, PtSn4, her student Samikshya Sahu had grown that had a HUGE RRR. The question: was something preventing defects from scattering electrons? Or were there just that few defects?

Wild and utterly short-sighted! 🤯
Curiously, we are seeing rapid growth in our program. Unclear why, but at least some students are coming from Comp Sci. Physics provides a broad based, rigorous cognitive framework for quantitative thought. I think students are recognizing this amid uncertainty.

At @apsphysics.bsky.social Global Physics Summit?
Check out Jörn Bannies’ presentation on electronically driven switching of the topology of LaSbTe Wed March 19 9:48-10am Anaheim convention center 255A!

At @apsphysics.bsky.social Global Physics Summit?
Check out Jiabin Yu’s presentation on emergent order in Pt-doped NbIrTe4, Thurs March 20 5:24-5:36 Anaheim convention center 252B!

At @apsphysics.bsky.social Global Physics Summit?
Check out Rysa Greenwood’s talk on dynamics at C60-Au(111) interfaces Tues, March 18 12:06-12:18 Anaheim convention center 254B!

Hey 🌎? Could you just quiet down a bit? Second quake in 2 weeks. No macroscopic damage, but the STMs do not like the spicy earth. TBH, I’m not really a fan either. 😬

earthquake.usgs.gov/earthquakes/...

I just got an email from DOE having reviewed for them before. Hard to read and believe the depth of it.

Oh, Sarah Burke is a VERY common name so it’s actually not that easy to track me down! No worries! Thanks very much for adding me!

Sarah Burke - Stewart Blusson Quantum Matter Institute My research interests broadly encompass the study of electronic processes where nanoscale structure influences or reveals the underlying physics. Using scanning probe microscopy (SPM) techniques, our ...

Yes! Here’s my institute profile page: qmi.ubc.ca/team-member/...
And google scholar: scholar.google.ca/citations?us...
Thanks! 😊

A few weeks ago we had a lot of fun showing CBC Vancouver's science reporter, Darius Mahdavi, around the Quantum Matter Institute. He *may* have mocked our excessive use of the word quantum (ok, fair!), but put together a great explainer of the world of quantum materials! www.cbc.ca/player/play/...

Got spectra? Sort them with k-means! We used k-means unsupervised clustering to categorize spectra in an electronically inhomogeneous materials, and found it works remarkably well when your eye says "those are different" (not so much otherwise). k-means: just try it! pubs.aip.org/aip/apl/arti...

Hi! We do Scanning Probe Microscopy on molecules to Quantum Materials! Part of the UBC Quantum Matter Institute.

We just found 10 surface scientists @🦋 #SciSky 🎉 Help us find more! #UHV #STM #XPS #UPS #ARPES #AFM #ChemPhys #PhySky #ChemSky #SurfSci #SurfaceScience
go.bsky.app/LKyQJm7

Thanks for helping us find each other over here!

Two-Stage Growth for Highly Ordered Epitaxial C60 Films on Au(111) As an organic semiconductor and a prototypical acceptor molecule in organic photovoltaics, C60 has broad relevance to the world of organic thin film electronics. Although highly uniform C60 thin films are necessary to conduct spectroscopic analysis of the electronic structure of these C60-based materials, reported C60 films show a relatively low degree of order beyond a monolayer. Here, we develop a generalizable two-stage growth technique that consistently produces single-domain C60 films of controllable thicknesses, using Au(111) as an epitaxially well-matched substrate. We characterize the films using low-energy electron diffraction, low-energy electron microscopy, scanning tunneling microscopy, and angle-resolved photoemission spectroscopy (ARPES). We report highly oriented epitaxial film growth of C60/Au(111) from 1 monolayer (ML) up to 20 ML films. The high-quality of the C60 thin films enables the direct observation of the electronic dispersion of the HOMO and HOMO–1 bands via ARPES without need for small spot sizes. Our results indicate a path for the growth of organic films on metallic substrates with long-range ordering.

Often the solution to getting good data is having good materials! In order to be able to do ARPES on C60 films, we had to work hard on making sure the films were uniform and well ordered. It turned out distilling the first ML was the way to go! Read more here: pubs.acs.org/doi/abs/10.1...

Time to boot up over here… posts on our recent papers and a proper profile and banner coming soon… 🕦

Oh, I did this 3 weeks ago (tripped up concrete stairs) and had bloody knuckles going back into a workshop and for a government official’s tour. 🤦🏻‍♀️ Just healed now. Annoying but could have been worse as you say!